Stamet’s last jump takes the Discovery into an alternate reality while completely incapacitating him. Lieutenant Tyler starts to realize there is more to his PTSD than meets the eye after he confronts L’Rell in the brig. The crew discovers that, in the future, the U.S.S. Defiant managed to cross over to this “mirror” universe and with that knowledge, set about a plan to find a way back home. DSC takes a turn in “Chapter Two” of its first season.